The present invention relates to a video/audio output device for outputting video and audio to an external speaker control apparatus which controls a speaker outside the video/audio output device.
In recent years, users are able to enjoy ambient audio, known generally as surround sound, by connecting an AV amplifier in between a plurality of speakers and a video/audio output device such as a TV, and outputting, from the plurality of the speakers connected to the AV amplifier, the audio of broadcast contents received by a TV tuner or a set top box (STB), or the audio of video contents reproduced by a DVD player/DVD recorder.
A user intending to output surround sound turns off (mutes) the audio outputted from the speaker (internal speaker) of the TV by operating the remote control button or the main button of the TV, and then, by operating a remote control button or the main button of the AV amplifier, causes input audio from the device, which is outputting the contents displayed by the TV, to be outputted from a speaker (external speaker) connected to the AV amplifier. In the process, the user is required first to operate the remote control button or a button on the console and then to operate a remote control button of the AV amplifier or a button on the AV amplifier. Since these operations must be performed for plural devices, the apparatuses above are not user-friendly.
In order to solve this problem, and to simplify the TV and AV amplifier operations when outputting the audio from the speaker (external speaker) connected to the AV amplifier, AV amplifiers have been realized in which an audio output source is switched by the on/off operation of the power supply switch on the AV amplifier.
Japanese Patent Laid-Open No. 5-153520 bulletin, for example, discloses an AV amplifier which can make up a surround system in combination with a TV receiver and which greatly facilitates the switching operation between use of the surround system and use of the TV receiver alone.
FIG. 1 is a block diagram showing the AV amplifier disclosed in Japanese Patent Laid-Open No. 5-153520.
In FIG. 1, when the surround system is used, a power supply switch 41 of the AV amplifier 40 is turned on, a change-over switch 50 is switched to a center audio amplifier circuit 48 side, and the audio signal supplied to an audio input terminal 43 from the reproduction device, such as a VTR or an LD, is supplied to the speaker connected to the AV amplifier 40 through a Dolby surround processor (DSP) 45 and an output terminal 49. When using the TV receiver alone, on the other hand, the power supply switch 41 of the AV amplifier 40 is turned off, the change-over switch 50 is turned to a TV audio input terminal 51 side, so that the TV audio processed in the amplifier circuit of the TV receiver is supplied to the speaker (internal speaker) of the TV receiver.
In the method disclosed Japanese Patent Laid-Open No. 5-153520, as described above, the audio is outputted from the speaker (internal speaker) built into the TV or the audio is outputted from the speaker (external speaker) outside the TV by switching the power supply switch of the AV amplifier between an on state and an off state.
Even when the power supply switch of the AV amplifier is turned from an off state to an on state, some TV receivers still output the audio from the internal speaker if the TV power supply is turned on after such change is made. In this case, the audio is outputted from both the internal and external speakers. Also, in the case where the user directly operates the TV or the AV amplifier, the audio can be set so as to not be outputted from the internal or the external speaker. The user desires that the audio is outputted from only one of the internal and external speakers.